"ri" <rupsyco@tm.net.my> wrote in message
news:445ad5b6$1_2@news.tm.net.my...
"GregS" <szekeres@pitt.edu> wrote in message
news:e25bv5$lgq$2@usenet01.srv.cis.pitt.edu...
In article <HZg1g.3800$4P2.3574@fe03.news.easynews.com>, The Ghost
theghost@hotmail.com> wrote:
"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a
pick-up,
I guess not as a mic would do, but often to check on resonance
frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you
see
breakup modes, but very simple ones, to focus on a cone vibrating
for
sympathy and gives you a signal from it's vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making
non-contact
measurement of vibration of which I am aware. Both systems measure
displacementMT and are therefore frequency limited. One is the I
photonic
sensor, for which the vibrating surface needs to be reflective to
light,
which can be accomplished by bonding a very thin reflective piece
of
aluminum foil at the measurement location. The other is a
capacitive
probe, for which the vibrating surface needs to be electrically
conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work
without
much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

grge
but lets say I want to pickup the signal of a resonant body like the
passive
radiator of a subwoofer, then a mic, even if nearby, will mainly
sense
the
"loud" signal of the driver...

On the cover of 6/1988 Speaker Builder magazine is a device hovering
over
the cone of an 8 inch driver, which is a Panasonic mic element.It has a
lever whereby the position
can be changed. This was for developing a map of the driver being
driven.

greg

i think there are ways to pre-filter the measured frequency. from what
i
saw
you get a cap of some sort that you put on the mic capsule and it
shriks
the
working/recieved freq. range.

I am in Malaysia, I don't know how to get that specific release of
Speaker
Builder. is there a link?

if let's say I use infrared, then I shall modulate a high frequency
signal
(40kHz i.e.), and using the FM coming out from doppler effect detect the
signal (does it make sense for a such relatively slow moving part to
cause
any shift in frequency for doppler effect?). Or I could measure the
change
in intensity of the reflected beam. Do you think ultrasounds would do?

The change in intensity should be fine. A little adjustment of angles and
reflectance.

I was thinking, there is probably non-linearity since doubling distance is
going to produce less than 1/2 the light.

greg
But if I'm just seeking the period to retrieve the frequency, it should be

"ri" <rupsyco@tm.net.my> wrote in message
news:445ad5b6$1_2@news.tm.net.my...
"GregS" <szekeres@pitt.edu> wrote in message
news:e25bv5$lgq$2@usenet01.srv.cis.pitt.edu...
In article <HZg1g.3800$4P2.3574@fe03.news.easynews.com>, The Ghost
theghost@hotmail.com> wrote:
"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a
pick-up,
I guess not as a mic would do, but often to check on resonance
frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you see
breakup modes, but very simple ones, to focus on a cone vibrating
for
sympathy and gives you a signal from it's vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making
non-contact
measurement of vibration of which I am aware. Both systems measure
displacementMT and are therefore frequency limited. One is the I
photonic
sensor, for which the vibrating surface needs to be reflective to
light,
which can be accomplished by bonding a very thin reflective piece of
aluminum foil at the measurement location. The other is a capacitive
probe, for which the vibrating surface needs to be electrically
conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work
without
much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

grge
but lets say I want to pickup the signal of a resonant body like the
passive
radiator of a subwoofer, then a mic, even if nearby, will mainly sense
the
"loud" signal of the driver...

On the cover of 6/1988 Speaker Builder magazine is a device hovering over
the cone of an 8 inch driver, which is a Panasonic mic element.It has a
lever whereby the position
can be changed. This was for developing a map of the driver being driven.

greg

i think there are ways to pre-filter the measured frequency. from what i
saw
you get a cap of some sort that you put on the mic capsule and it shriks
the
working/recieved freq. range.

I am in Malaysia, I don't know how to get that specific release of Speaker
Builder. is there a link?

if let's say I use infrared, then I shall modulate a high frequency signal
(40kHz i.e.), and using the FM coming out from doppler effect detect the
signal (does it make sense for a such relatively slow moving part to cause
any shift in frequency for doppler effect?). Or I could measure the change
in intensity of the reflected beam. Do you think ultrasounds would do?

The change in intensity should be fine. A little adjustment of angles and
reflectance.

I was thinking, there is probably non-linearity since doubling distance is
going to produce less than 1/2 the light.

"ri" <rupsyco@tm.net.my> wrote in message
news:445ad5b6$1_2@news.tm.net.my...
"GregS" <szekeres@pitt.edu> wrote in message
news:e25bv5$lgq$2@usenet01.srv.cis.pitt.edu...
In article <HZg1g.3800$4P2.3574@fe03.news.easynews.com>, The Ghost
theghost@hotmail.com> wrote:
"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a
pick-up,
I guess not as a mic would do, but often to check on resonance
frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you see
breakup modes, but very simple ones, to focus on a cone vibrating
for
sympathy and gives you a signal from it's vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making
non-contact
measurement of vibration of which I am aware. Both systems measure
displacementMT and are therefore frequency limited. One is the I
photonic
sensor, for which the vibrating surface needs to be reflective to
light,
which can be accomplished by bonding a very thin reflective piece of
aluminum foil at the measurement location. The other is a capacitive
probe, for which the vibrating surface needs to be electrically
conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work
without
much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

grge
but lets say I want to pickup the signal of a resonant body like the
passive
radiator of a subwoofer, then a mic, even if nearby, will mainly sense
the
"loud" signal of the driver...

On the cover of 6/1988 Speaker Builder magazine is a device hovering over
the cone of an 8 inch driver, which is a Panasonic mic element.It has a
lever whereby the position
can be changed. This was for developing a map of the driver being driven.

greg

i think there are ways to pre-filter the measured frequency. from what i
saw
you get a cap of some sort that you put on the mic capsule and it shriks
the
working/recieved freq. range.

I am in Malaysia, I don't know how to get that specific release of Speaker
Builder. is there a link?

if let's say I use infrared, then I shall modulate a high frequency signal
(40kHz i.e.), and using the FM coming out from doppler effect detect the
signal (does it make sense for a such relatively slow moving part to cause
any shift in frequency for doppler effect?). Or I could measure the change
in intensity of the reflected beam. Do you think ultrasounds would do?

The change in intensity should be fine. A little adjustment of angles and
reflectance.

"ri" <rupsyco@tm.net.my> wrote in message
news:445ad5b6$1_2@news.tm.net.my...
"GregS" <szekeres@pitt.edu> wrote in message
news:e25bv5$lgq$2@usenet01.srv.cis.pitt.edu...
In article <HZg1g.3800$4P2.3574@fe03.news.easynews.com>, The Ghost
theghost@hotmail.com> wrote:
"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a
pick-up,
I guess not as a mic would do, but often to check on resonance
frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you see
breakup modes, but very simple ones, to focus on a cone vibrating
for
sympathy and gives you a signal from it's vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making
non-contact
measurement of vibration of which I am aware. Both systems measure
displacementMT and are therefore frequency limited. One is the I
photonic
sensor, for which the vibrating surface needs to be reflective to
light,
which can be accomplished by bonding a very thin reflective piece of
aluminum foil at the measurement location. The other is a capacitive
probe, for which the vibrating surface needs to be electrically
conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work
without
much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

grge
but lets say I want to pickup the signal of a resonant body like the
passive
radiator of a subwoofer, then a mic, even if nearby, will mainly sense
the
"loud" signal of the driver...

On the cover of 6/1988 Speaker Builder magazine is a device hovering over
the cone of an 8 inch driver, which is a Panasonic mic element.It has a
lever whereby the position
can be changed. This was for developing a map of the driver being driven.

greg

i think there are ways to pre-filter the measured frequency. from what i
saw
you get a cap of some sort that you put on the mic capsule and it shriks
the
working/recieved freq. range.

I am in Malaysia, I don't know how to get that specific release of Speaker

Builder. is there a link?

if let's say I use infrared, then I shall modulate a high frequency signal
(40kHz i.e.), and using the FM coming out from doppler effect detect the
signal (does it make sense for a such relatively slow moving part to cause
any shift in frequency for doppler effect?). Or I could measure the change
in intensity of the reflected beam. Do you think ultrasounds would do?

"ri" <rupsyco@tm.net.my> wrote in message
news:445ad5b6$1_2@news.tm.net.my...
"GregS" <szekeres@pitt.edu> wrote in message
news:e25bv5$lgq$2@usenet01.srv.cis.pitt.edu...
In article <HZg1g.3800$4P2.3574@fe03.news.easynews.com>, The Ghost
theghost@hotmail.com> wrote:
"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a pick-up,
I guess not as a mic would do, but often to check on resonance
frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you see
breakup modes, but very simple ones, to focus on a cone vibrating for
sympathy and gives you a signal from it's vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making non-contact
measurement of vibration of which I am aware. Both systems measure
displacement and are therefore frequency limited. One is the MTI
photonic
sensor, for which the vibrating surface needs to be reflective to light,
which can be accomplished by bonding a very thin reflective piece of
aluminum foil at the measurement location. The other is a capacitive
probe, for which the vibrating surface needs to be electrically
conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work without
much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

grge
but lets say I want to pickup the signal of a resonant body like the
passive
radiator of a subwoofer, then a mic, even if nearby, will mainly sense the
"loud" signal of the driver...

On the cover of 6/1988 Speaker Builder magazine is a device hovering over
the cone of an 8 inch driver, which is a Panasonic mic element.It has a lever whereby the position
can be changed. This was for developing a map of the driver being driven.

greg

Quote:

i think there are ways to pre-filter the measured frequency. from what i saw
you get a cap of some sort that you put on the mic capsule and it shriks the
working/recieved freq. range.

"The Ghost" <theghost@hotmail.com> wrote in message
news:8U87g.117427$2g2.61584@fe07.news.easynews.com...

Quote:

"Neky Lyk" <ned@m.mejl> wrote in news:e3j4ck$shm$1@ss408.t-com.hr:

"ri" <rupsyco@tm.net.my> wrote in message
news:445ad5b6$1_2@news.tm.net.my...
"GregS" <szekeres@pitt.edu> wrote in message
news:e25bv5$lgq$2@usenet01.srv.cis.pitt.edu...
In article <HZg1g.3800$4P2.3574@fe03.news.easynews.com>, The Ghost
theghost@hotmail.com> wrote:
"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a
pick-up, I guess not as a mic would do, but often to check on
resonance frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you
see breakup modes, but very simple ones, to focus on a cone
vibrating for sympathy and gives you a signal from it's
vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making
non-contact measurement of vibration of which I am aware. Both
systems measure displacement and are therefore frequency limited.
One is the MTI
photonic
sensor, for which the vibrating surface needs to be reflective to
light, which can be accomplished by bonding a very thin reflective
piece of aluminum foil at the measurement location. The other is a
capacitive probe, for which the vibrating surface needs to be
electrically conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work
without much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

grge
but lets say I want to pickup the signal of a resonant body like the
passive
radiator of a subwoofer, then a mic, even if nearby, will mainly
sense the "loud" signal of the driver...

i think there are ways to pre-filter the measured frequency. from what
i saw you get a cap of some sort that you put on the mic capsule and
it shriks the working/recieved freq. range.

You really need to get off the drugs.

nah. i like them they help me. you don't wanna see what happens when i
don't

"ri" <rupsyco@tm.net.my> wrote in message
news:445ad5b6$1_2@news.tm.net.my...
"GregS" <szekeres@pitt.edu> wrote in message
news:e25bv5$lgq$2@usenet01.srv.cis.pitt.edu...
In article <HZg1g.3800$4P2.3574@fe03.news.easynews.com>, The Ghost
theghost@hotmail.com> wrote:
"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a
pick-up, I guess not as a mic would do, but often to check on
resonance frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you
see breakup modes, but very simple ones, to focus on a cone
vibrating for sympathy and gives you a signal from it's
vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making
non-contact measurement of vibration of which I am aware. Both
systems measure displacement and are therefore frequency limited.
One is the MTI
photonic
sensor, for which the vibrating surface needs to be reflective to
light, which can be accomplished by bonding a very thin reflective
piece of aluminum foil at the measurement location. The other is a
capacitive probe, for which the vibrating surface needs to be
electrically conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work
without much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

grge
but lets say I want to pickup the signal of a resonant body like the
passive
radiator of a subwoofer, then a mic, even if nearby, will mainly
sense the "loud" signal of the driver...

i think there are ways to pre-filter the measured frequency. from what
i saw you get a cap of some sort that you put on the mic capsule and
it shriks the working/recieved freq. range.

"ri" <rupsyco@tm.net.my> wrote in message
news:445ad5b6$1_2@news.tm.net.my...

Quote:

"GregS" <szekeres@pitt.edu> wrote in message
news:e25bv5$lgq$2@usenet01.srv.cis.pitt.edu...
In article <HZg1g.3800$4P2.3574@fe03.news.easynews.com>, The Ghost
theghost@hotmail.com> wrote:
"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a pick-up,
I guess not as a mic would do, but often to check on resonance
frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you see
breakup modes, but very simple ones, to focus on a cone vibrating for
sympathy and gives you a signal from it's vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making non-contact
measurement of vibration of which I am aware. Both systems measure
displacement and are therefore frequency limited. One is the MTI
photonic
sensor, for which the vibrating surface needs to be reflective to light,
which can be accomplished by bonding a very thin reflective piece of
aluminum foil at the measurement location. The other is a capacitive
probe, for which the vibrating surface needs to be electrically
conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work without
much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

grge
but lets say I want to pickup the signal of a resonant body like the
passive
radiator of a subwoofer, then a mic, even if nearby, will mainly sense the
"loud" signal of the driver...

i think there are ways to pre-filter the measured frequency. from what i saw
you get a cap of some sort that you put on the mic capsule and it shriks the
working/recieved freq. range.

"GregS" <szekeres@pitt.edu> wrote in message
news:e25bv5$lgq$2@usenet01.srv.cis.pitt.edu...

Quote:

In article <HZg1g.3800$4P2.3574@fe03.news.easynews.com>, The Ghost
theghost@hotmail.com> wrote:
"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a pick-up,
I guess not as a mic would do, but often to check on resonance
frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you see
breakup modes, but very simple ones, to focus on a cone vibrating for
sympathy and gives you a signal from it's vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making non-contact
measurement of vibration of which I am aware. Both systems measure
displacement and are therefore frequency limited. One is the MTI photonic
sensor, for which the vibrating surface needs to be reflective to light,
which can be accomplished by bonding a very thin reflective piece of
aluminum foil at the measurement location. The other is a capacitive
probe, for which the vibrating surface needs to be electrically
conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work without
much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

grge
but lets say I want to pickup the signal of a resonant body like the passive

radiator of a subwoofer, then a mic, even if nearby, will mainly sense the
"loud" signal of the driver...

"GregS" <szekeres@pitt.edu> wrote in message
news:e25bv5$lgq$2@usenet01.srv.cis.pitt.edu...

Quote:

In article <HZg1g.3800$4P2.3574@fe03.news.easynews.com>, The Ghost
theghost@hotmail.com> wrote:
"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a pick-up,
I guess not as a mic would do, but often to check on resonance
frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you see
breakup modes, but very simple ones, to focus on a cone vibrating for
sympathy and gives you a signal from it's vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making non-contact
measurement of vibration of which I am aware. Both systems measure
displacement and are therefore frequency limited. One is the MTI
photonic
sensor, for which the vibrating surface needs to be reflective to light,
which can be accomplished by bonding a very thin reflective piece of
aluminum foil at the measurement location. The other is a capacitive
probe, for which the vibrating surface needs to be electrically
conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work without
much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Dear All,

I've seen vibrations measurement systems that use laser as a pick-up,
I guess not as a mic would do, but often to check on resonance
frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you see
breakup modes, but very simple ones, to focus on a cone vibrating for
sympathy and gives you a signal from it's vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making non-contact
measurement of vibration of which I am aware. Both systems measure
displacement and are therefore frequency limited. One is the MTI photonic
sensor, for which the vibrating surface needs to be reflective to light,
which can be accomplished by bonding a very thin reflective piece of
aluminum foil at the measurement location. The other is a capacitive
probe, for which the vibrating surface needs to be electrically conductive,
which can be accomplished by spraying it with a conductive paint.

A simple IR emitter detector mounted together will tend to work without
much concern with reflectance.
A small microphone capsule held close to the surface
has also been used.

"Riccardo Balistrerri" <riccardo.balistreri@poste.it> wrote in
news:44458800$1_1@news.tm.net.my:

Quote:

Dear All,

I've seen vibrations measurement systems that use laser as a pick-up,
I guess not as a mic would do, but often to check on resonance
frequencies of cones i.e.

I'm not talking about the very expensive systems that lets you see
breakup modes, but very simple ones, to focus on a cone vibrating for
sympathy and gives you a signal from it's vibrations.

Anybody can tell me where to get them, and how do they work?

Thanks,
R.

There are only two relatively inexpensive systems for making non-contact
measurement of vibration of which I am aware. Both systems measure
displacement and are therefore frequency limited. One is the MTI photonic
sensor, for which the vibrating surface needs to be reflective to light,
which can be accomplished by bonding a very thin reflective piece of
aluminum foil at the measurement location. The other is a capacitive
probe, for which the vibrating surface needs to be electrically conductive,
which can be accomplished by spraying it with a conductive paint.